Fluid pressure tool



Oct. 17, 1933 E. w. STEVENS 1,931,041 FLUID PRESSURE TOOL Filed Feb. 27, 1930 /2 Tx \\\\A\\ A TTORNEY.

patented Oct. 17, 1933 ,UNITED` ST4 rain-1,041

ruim PRESSURE 'rooL lj vEawora w. stevens, rDon-oit. Mioh.; signor to f Chicago Pneumatic ToolCompany; Newl-Ifork,

, 'Anpuoation Fobrnory 27, 1930. senat No. 431.6sol f izclaimo. (Grin-19).", f f opposedV arcuate seats -10 and llffofsubstantial 'extent alternatelyengagedbythe ring valve '8 This invention relates to fluid pressuretools of' the percussive type Iin"geri'er'al 'and more particularlyl to those having a' free exhaust in the cylinder control1ed=only` by the impact piston and having an automatically'v operated valve which controls the admission of motive iiuid` in alternation to the opposite'ends of the piston chamber. 1 i f 'Y One object of the invention is to improve the constructionv and operation of tools of the described type.v Another object is to develop a control valve` whi`ch is 'lightin weight, occupies a very small space, and` can be mounted directly upon the cylinder or upon aback head for the same, thereby to -produce an extremelysimple, 'o

light, and compact tool. `'Other objects will be apparent from the detailed "description which Vfollows.` A

In order to illustrate the inventionconcrete embodiments thereof are shown *in `the panying :drawing in which: v v 'Figf 1` is alongitudinal sectional view Vof a Apneumatic hammer with-:thexicylinder partly -broken away and showing aportion of the grip handleV in elevationythe.` section being substantiallyonthe line 1 -1"of Fig. 3; i Fig; 2.1is-.a' sectional view ofthe Samehammer shown' 'in Fig. f1 but with" the handle .cut away, the valve and piston/.1v being .in different positions Aand the. sectionv being ori'the-line. 2-2 of Fig.3; i* 'y Fig. 3 is a `transverse. sectional'view substantially'on the vline 3-3 of Fig. 2; y i Fig.-4 is' a sectional view similar toFig. 2 but showing a modiiication and i uFigQ is a transverse sectional viewzon the line 5 5 ofFig. 4.1 'i n o In thefform of. the 'invention shown Vin Figs. A1 3 the hammer comprisesa cylinder .6 within which reciprocates an-v impactlpiston -'l, the ,movement of which iscontrolled byan automatically thrown distributing valve. 8. The

end of cylinder 6 ,fwithin head extension 941 is` :reduced tov form an elliptical projectionr 6a.-` with accomi which telescopes over projection Gil/ and engages `with its one edge tiiostonshoulder, sbfformed j by the reduced projection while itsopposite edge slidably'engages head 9.V vSeatlO has ports r`12 vtherein which connectl through passages* 12a with the front end of the piston 'chamberwhile the opposing seat l1 has *ports 13- therethrough opening directly into' therearz endof thepiston 55 chamber. `Fluid inlet 9dr.- opens directly into annular chamber 14 so that vthe-'outer face' of vvalve 8 is subjected -at all points'to'live'motive fluid..,'

` Four constant press re passages lglarepro- 7 vided, two `in each` of y efopposed seats lpan'd 11y and von opposite sides oi ports 12 andiA 13,

asshown in Fig."y3.- ThesepassagesfopeniintO 'Il iveair'chamber 141b`y` ports 11,5;beyondfistop fshoulderjgb, as indicated 'ih Fig. 2 fandrconductv the motiveiluid to'jthe inner orcontrol'face of the valve.' The size ofv ,passages 15a. andports 15 is determined byexperifmentfwith hammers, .of various' sizes [t give'the bestresults. They may be'of different sizfefiorl opposed Vseatsllzi .i Valve 8 controls' on'lyfthe admission I of; motive fluid to tliehammer".the exhaust from the piston chamber being provided for `,by ports-16" under control Vof piston '1 4leading directlyA toatmosphere.y The throwing of the'valve isaccornplish-v ed by a combination of'constant presure on}thfe outer face of the valve togetherv witli reduced 'pressure at one of thevalveseats produced when i piston' 7`uncove`r`s eitherr of the spaced-"exhaust 90 2 shows the pistonfon its power orV blow stroke. 95

The form 4of the invention sijiownin Figsqi-s, Vis characterized by extreme simplicity,c' omt 'ness anda minimum number of parts. Itelirnifnates v'the use of a valve block andfdowel and since the piston chamber passes through' the Figs. 4 and 5A.is` just asi eiiicientfromfanoperating standpoint as-theV previously described form ibut additional parts. rnstead-iorjforming the fyaive `"valve it permits the Ashortest' possibleoverall i 'lengtlr for the'ham'mer" f seats 'as an integral 'part of cylinder 6', aseparateY valve block 1'7 is'l provided iniixed'frelation-to cylinder v 6` and interposed between nie lotion and VV110 cylinder 6,. leading to the front end of the piston chamber while ports 13 lead from the opposite valveseat directly into the front end of the piston chamber.

15a in the first form, .communicate with the live air chamber by ports 18 (Fig. 4) andconduct live y air to the inner controlgface of the valve.

A convenientway of formingthe ellipticalpro-fff jection for valves 8 and 8 and the seatsengaged by the same is to reduce the end of cylinder 6 (Figs. 1-3) or of cylinder head blockfl'l y(Figa` 4 and 5) to a predetermined diameter, conforming to that of the inner face of the valve and td a depthgsuiientto take the full Width of the ,vali/,11 'Chus Vforming stopk shoulder 6bv or, 1471). Ifhezresulting ,projectionis then recut on one side off center'into/the, form ofan ellipse, eut-being of substantially the same radius as .thejirst cut. This givesa seat area equivalent to approximatelyfhalf of the,valve,all of whichis .uncovered uponavvery slight movement of the letter-y, Y i c f kA, ring valveY externally arranged asherem 4dieclosed sogas to utilize its inner face for con- Y-trolof the motive iluid not only permits a simple ,andoompact tool but ,also one which is economical both in the original cost of manufacturey and inmgkeeprz The, valvecan be made very light in with very short movement, thus yproduc- ,ipg5guiclr action and a Aminimum of Wear upon :itsy mounting member. Furthermore the exter- ,nallygmounted valve provides .more area for its vlength.than thesinall external-,Valves heretofore 11S-ed, thereby producing faster pistonH action and aheavier blow.y n 4 '.'I-claim as my invention :A

. 1; A uid pressure 'tool having a cylinder pro- ".f. a pistonchamber, a piston reciprocable therein, and a ring valve having a plain inner `face,telescopingly engagingthe exterior of said .cy'rlinder and movable transversely thereof, for QOJltrQlling the .distribution of motive uid to ggqjprpcate` said piston," said Icylinder' having pertain they portionv engaged by vsaid valve lead-V to the opposite ends of said piston chamber. v2,. A,- fluidpressure toolhaving a cylinder, a piston reciprocable therein, said cylinder having gopposed arcuate seats onits exterior.. and, ports,

thereingextendingto the opposite ends of the fpjstonehfmber, anda ring valve.telescoped over saidcylinder for alternately engaging said seats to control thedistribution .of motive fluid. to the i lziist'nri chamber.

fluid pressure tool 4having al. cylinder, a pistonreciprocable therein, said cylinderv being reduced at one` end to; provide andannular stop vel,ioiiller and having opposed arcuate seats in i115. ledlld portion, and a ring .valve telescoped y,Over-V saidV reduced portion and,y in engagement vWith said stop shoulder, the inner-face of said valves'epliagingr-said-Y seats inalternatilon. j

4; A;-fiuid ,pressure percussive tool having a Aylinder with1 an elliptical extension, a., piston i reciprocable within said '.cylinder, ahead secuig-:dtov saidcylinder over saidr extension; and Rvldmggaa Conduit for motive fluid, andv means .within aridiheed kforeffecting distribution" of Constant Vpressure passagesy 18a, similar in number and position to passages,

seat to shift the valve. y

' rsaid projection `vvith its edgesislidably engaging Vproviding an elliptical projection having valve Vring valve of greater diameter than said piston telescoped over rsaid extension of said cylinder.

5. A fluid vpressure percussive tool having a cylinder, a piston reciprocable therein, a head inclosing one end of said cylinder and secured tothe latter, a ring valve Withinsaid head havingone edge in sliding contact with Athe same and having va smooth, annular, unbroken inner face, and means utilizing the inner face of said Valve for distributing motive fluid in alternation to the opposite ends of said cylinder to reciproicate said piston.

.K 6. A uid pressureA percussive tool having av cylindena pistonreciprocable therein, a'head securedto said cylinder and closing one end of the latter, meansy within said head at the rear- .other seatis engagedby said valve, and means for introducing pressure fluidthrough said other 'LA fluid ypressure percussive tool` having ai cylinder, a piston reciprocable therein, a head secured to` said cylinder and closing one end of .the latter, said cylinder end being reducedto 7105 provide an annular. -stop shoulder` and having opposed arcuate seats in said reduced portion, andv a ring` valve'telescoped overfsaid reduced portion formovement transversely of saidl cyl-l inder to engage said -seats in'alternation and :110 of a size to provide clearance at the unengaged seat for .the passage-of motive ud, theedges of said valve slidably engaging said head and said shoulder. 5 fi 8. A fluid pressure percussive4 tool havingfa m5 cylinder, a piston reciprocableatherein,axhead securedv to said cylinder, means Within saidghead providing opposed arcuate seats vdisposedA inv the ksame transverse: plane andi-ports inl said' seats leadingl tov-thelopposite ends of said cylinder, 7120 an imperforate ring valve .havingfa smooth, annular-, inner face,r said' valve controlling ysaid .ports with its '.inneriface, means subjecting vthe outer facefof saidfvalve..;to. motive fluid, and

of saidvalve adjacent said ports. ,l

9., As fluid :pressurepercussiv'e tool having a cylinder, a piston reciprocable therein", ahead secured to said.cylinder,.means `Within said head providing an ellipticallprojection havingffva-lve vseats on the oppositesides thereofz and ports leading therefrom to the'opposite yendsV of said cylinder,` said projection having an 4annulars'top shoulder, airing valve -telescopinglyv engaging said :shoulder on" the one hand and saidv lhead on the other for` engaging saidseats in alternar, tion withrits inner facepmeans subjectingV the outer-face ofgsaid valve to motive fluid, Aand -means for feeding 'motive .fluid toVv the inner face. of said valve 'adjacent said ports.

10. A fluid-pressure percussivetool having a cylinder; a piston reciprocable therein; a head secured tofsaid cylindenmeans Within said head 1&5

seats Lonl the' opposite vsides thereof and ports leading therefrom v'to the opposite ends of rsaid cylinder, saidprojectionhaving .an annular stop shoulder, a ring valve telescopingly engaging said mq, projection withits edges slidably engagingY said 'f shoulder on the one hand and saidhead on the other for engaging said seats in alternation with its inner face, said tool providing a live air chamber about said valve thereby continuously subjecting the entire outer face of said valve to motive fluid, a-nd means for feeding motive fluid from said chamber to the inner face of said valve adjacent said ports comprising passages opening intoV said chamber vbeyond said stop shoulder.

11. A iiuid pressure tool having a cylinder provided with a reduced portion or extension at its rear end, a piston reciprocable within said cylinder, a narrow, imperforate and unbroken ring valve telescoped over said reduced portion of said cylinder and means including Valve seats 'integral member` and ports in said reduced portion v'of said cylinder controlled by theinner face of said valve for distributing motive fluid in alternation to the opposite ends of said cylinder to reciprocate said piston.

y 12. Ina fluid pressure tool, a support generally' ter so that said support` is slightly elliptical' whereby` a ring valve having a plain inner surface conforming to the radius of said faces will have clearance at one face when it engages the other face, said support comprising a single EDWARD W. STEVENS." 

